1994 and earlier 4.0l Rangers use an EDIS-6 module for spark.
The CKP(crank position) sensor connects to the EDIS-6 module
EDIS-6 connects to coil pack.
It is a separate spark system, 1995 and up used newer computer and it runs spark.
The EDIS-6 module does send the CKP sensor timing to the computer(EEC/ECU/PCM), so computer can time the fuel injectors.
If CKP sensor had a problem then No Spark, along with no fuel injectors.
So CKP, EDIS and coil pack are OK if engine starts by adding fuel manually.
So problem will be in the wiring between EDIS module and computer, Computer itself or the wiring at the fuel injectors
Is the computer starting up?
Does the CEL(check engine light) come on when key is turned on?
Do you hear the fuel pump come on for 2 seconds when key is turned on?
Computer runs the fuel pump.
If CEL comes on and fuel pump runs for 2 seconds then computer is probably OK.
When you turn on the key all the fuel injectors should get 12volts, there is a Red wire that just daisy chains from one injector to the next that should have 12volts when ever key is on.
Test for voltage at fuel injectors
The computer GROUNDS the injectors to open them.
'94 and earlier will use Batch Fire fuel injection, on a V6 this means that the computer GROUNDS 3 fuel injectors at the same time to open them.
So there will be TWO ground wires coming from the computer, a White wire and a Tan wire, each wire will connect to 3 separate injectors.
Diagram here of the injector wiring and also the EDIS wiring to computer: http://www.therangerstation.com/tech...0_3_0_2of3.JPG
The EDIS is where the timing pulse comes from to open the injectors.
Both Ground wires failing at the same time would be very very long odds.
Red power wire could be damaged, which would stop all injectors.
Timing pulse wire from EDIS could be bad.
Computer has a 60-pin connector, if there was water intrusion then that could effect specific systems.
Good look here at your computer and wiring: Ford EEC-IV
Pin 56 is the PIP, the CKP pulse from EDIS module, that tells computer that Crank is turning and times the fuel injectors
You can open it, warranty is long over, lol, and make sure circuit board is OK, not damaged
One long shot and only ever read about it happening one time, bad TPS(throttle position sensor)
The computer has a Clear Flooded Engine Routine, this shuts off fuel injectors while cranking the engine to dry it out, spark stays on.
The TPS gets 5volts from computer, TPS sends back .6 to .9volts if throttle is closed
As gas pedal is pushed down throttle plate opens the TPS voltage will increase, at wide open throttle(WOT) the voltage back to computer will be above 4.5volts.
To start Clear Flooded Engine Routine, you turn the key on and press gas pedal to the floor, so computer is seeing above 4.5volts from TPS but no CKP pulse, engine off.
Computer won't ground injectors now, so no fuel.
Computer will start fuel injectors as soon as TPS voltage drops below 4.5volts.
If there was a short in the TPS or its wiring then computer could be "seeing" above 4.5volts any time key is on, so no fuel injectors.
Unplug TPS and try to start engine
Test TPS wires, key on, only 1 should have 5volts